TO:
Texas Air Research Center (or Texas Hazardous
Waste Research Center)
FROM:
Investigators: Sidney Lin
Institution: Lamar University
Contact Information: 409-880-2314
SUBJECT:
Annual Progress Report
PROJECT NUMBER: 513LUB00208
PROJECT TITLE:
Detection of Nitrogen Oxides in Automobile Exhaust
by Nanoceramic Sensor
PROJECT PERIOD:
9/1/2013 – 7/15/2014
DATE:
9/15/2014
Project Description
This two-year project is to manufacture a fast-response high-accuracy sensor for
nitrogen oxides (NOx) detection using chemically stable high-surface-area ceramic
nanowires. To achieve this goal, ceramic nanowires will be first formed from ceramic
slurry via the electrospinning process followed by a high temperature sintering in a
controlled atmosphere. The wires will then be integrated with an electrical circuit to be a
portable sensor. Finite element analysis will be employed to modify the electrospinning
process to control the dimension and porosity of the spun nanowires in order to
increase the surface area of the spun nanowires and thus maximize the detection
sensitivity of the sensor. The sintering process will be modified to maximize the surface
area and control the nanostructure of the synthesized wires in order to improve the
sensor performance. The first year deliverables will be a custom made electrospinning
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system for ceramic nanowires preparation. The second year deliverables will include a
one dimensional mathematic model to analyze the electrospinning process, and
nanowires of three different compositions. In addition to the PI, one graduate student
and two undergraduate students will work on this project.
Objectives
The overall goal of this project is to produce a NOx sensor that is portable, fast
response, with high selectivity and high accuracy. We will assemble a prototype sensor
using nanoceramic wires which will not only reduce the size and weight of the sensor
but also will have very low detection limit and fast response time due to its very high
specific surface area. With the fast detection capability, NOx can be detected and then
treated/reduced quickly. The success of this project will benefit the air pollution
control/reduction and improve the air quality and living environment in Texas.
Methodology
Recent progress in solid state sensors provides a new opportunity to improve the
detection of trace gases (e.g. NOx, carbon dioxide, methane, and ethanol) at very low
concentrations (in ppb range). We propose to use the nanoceramic wire concept to
design and assemble a sensor to detect NOx of low concentrations.
The success of this project objective will be achieved/evaluated by the following steps:
1. Selection of sensor materials (detailed literature search).
2. Production of nanoceramic wires of the desired compositions by electrospinning
process.
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3. Sintering the spun wires to form high surface solid nanowires.
4. Improvement the sintering process and electrospinning process by mathematical
modeling (finite element analysis).
5. Assembly and test a sensor device to detect NOx.
There are three tasks in this project.
Task 1. Preparation of NanoCeramic Wires via Electrospinning Process
Task 2. Sintering of Spun Nanowires and Assembly of Sensor
Task 3. Development of a mathematical model to simulate the electrospinning process
Accomplishments/Problems
Equipment
The most important equipment for this project, a high voltage power supply (Figure 1) to provide
necessary electric field for the electrospinning process has been purchased and installed. The
integration of this power supply and syringe pump (Figure 2) that will deliver the reactant
solution has been set up as proposed in the proposal.
(a)
(b)
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Figure 1. (a) The front view of the high voltage power supply, (b) The back panel of the high
voltage power supply.
(a)
(b)
Figure 2. (a) The syringe pump that will be used to control the delivery rate of reactant
solutions, (b) Various sizes of syringes that will used to deliver the reactant solutions.
Personnel
One Ph.D. student and two undergraduate students were recruited to conduct this project. The
PI used one full summer month in year 2014 to conduct experiments, train students to operate
the experimental setup, and teach them using the COMSOL MultiPhysics program to build a
mathematic model. The PI attended the 3rd International Conference on Electrospinning in San
Francisco to collect information and build up network with researchers in the electrospinning
research for future collaboration.
Future Work
We will use the second year to produce nanoceramic wires via electrospinning process
and sinter the spun nanowires and develop the mathematical model to study the
electrospinning process.
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